Composite electrical connectors, which are intended to meet the usage requirements of multi-functionality and economical volume and are able to conform to a variety of signal transmission standards, have become the trend in the development of electrical connectors. In particular, because signal transmission standards are constantly being updated, composite electrical connectors that can simultaneously handle old and new transmission standards during the transition period from old to new transmission standards are able to increase ease of use.
The signal transmission formats most commonly used at present are USB 2.0, USB 3.0 (USB being an abbreviation for “universal serial bus”) and ESATA (which is an abbreviation for “external serial advanced technology attachment”), and for that reason composite socket electrical connectors have been developed into which USB 2.0, USB 3.0 and ESATA plug connectors can be separately plugged, such as that disclosed by Taiwanese Utility Model Publication No. M357748 (corresponding Chinese Patent Application No. 200810173163.4; corresponding U.S. Patent Publication No. US2009111330A1). The structure disclosed in Patent No. M357748 comprises three types of terminals, wherein the first type of terminal is a terminal for an ESATA connector, the second type of terminal is a terminal for a standard USB 2.0 connector, and the third type of terminal acts with the second type of terminal to form together a terminal for a USB 3.0 connector, the third type of terminal being integrated with the tongue and buried within the tongue, the first type of terminal being installed on the upper surface of the tongue, and the second type of terminal being installed on the lower surface of the tongue. Referring to FIG. 8 of the above specification and related description, the point of intersection between the upper surface of the tongue and rear wall integrally form a thickened part, while the first terminal slot fitted onto the tongue upper surface to house the first type of terminal also penetrates the thickened part, and the increased strength provided by the thickened part facilitates the securing of the fixed part of the terminal. However, the structural strength of the split assembly tongue in itself is comparatively weak due to the comparatively thin thickness thereof; and cannot easily bear insertion/removal force or rotational torque, or is liable in conditions of non-normal insertion/removal to result in a state where the tongue is loosened or fractured and so on. The thickened part increases the thickness of the tongue in order to strengthen the security of the corresponding terminal fixed part but because the thickened part is perforated and segmented by the plurality of first terminal slots, provides little contribution towards strengthening the entire body of the tongue. In addition, in the first type of terminal, a long and straight board-shaped contact part extends forwards from the fixed part, and this contact part of the first type of terminal is simply placed inside the first terminal slot of the tongue surface, thus it cannot be secured in place and tendency to be deformed or buckled. Consequentially, certain individuals would appreciate an improved connector.